The advocacy group Mental Health Movement made its claims about Emanuel in a Facebook post following the event. The post detailed how two of the group's members, Debbie Delgado and Matt Ginsberg-Jaeckle, confronted Emanuel and sharply criticized him for closing mental health clinics.

"After trying to keep his cool, he told us that he would speak to us after the event in a separate room. There, we saw the Real Rahm. Now off camera, Rahm's voice raised, his demeanor changed, in no time he was shouting in Matt's face, nose-to-nose," the post read.

And that's when things allegedly got out of hand.

"YOU'RE GONNA RESPECT ME!" Emanuel is quoted shouting at Ginsberg-Jaeckle, who is no stranger to antagonizing the mayor.

Reached for comment, Emanuel's government office referred Business Insider to his reelection campaign, which released a statement disputing the advocates' claims about their meeting with the mayor.

"As Rahm consistently meets with Chicagoans who have a different point of view about the challenges facing the city," said his campaign spokesman, Steve Mayberry. "Rahm spent about an additional 15 minutes in a private discussion with her to take her thoughts into consideration and direct her to resources that can address her needs. Rahm's 15-minute private meeting ended very cordially, with the mayor thanking them for giving him issues and concerns to check into and consider."

Regardless, the alleged outburst would not necessarily be out of character for Emanuel, a former congressman and White House chief of staff. In one infamous story, Emanuel is said to have sent a dead fish to a pollster who displeased him. In another, Emanuel suddenly pulled out a knife at a dinner table, shouted the name of a political enemy, slammed the knife into the table, and yelled, "Dead!"

"They say your greatest strength is also your greatest weakness. I'm living proof of that," Emanuel says, straight to the camera, in the ad. "I can rub people the wrong way, or talk when I should listen. I own that. But I'm driven to make a difference."